function getMean(array, len){
  var sum = 0
  for(var i=0;i<len;i++){
    sum += array[i]
  }
  return sum/len
}

function formatTime(date) {
  var year = date.getFullYear()
  var month = date.getMonth() + 1
  var day = date.getDate()
  var hour = date.getHours()
  var minute = date.getMinutes()
  var second = date.getSeconds()
  return [year, month, day].map(formatNumber).join('/') + ' ' + [hour, minute, second].map(formatNumber).join(':')
}
const formatNumber = n => {
  n = n.toString()
  return n[1] ? n : '0' + n
}

function getMaxValue(array){
  return Math.max(...array).toFixed(5)
}

function getMinValue(array){
  return Math.min(...array).toFixed(5)
}

function getDataArray(array) {
  return array.map(item => {
    return item.toFixed(5)
  })
}

module.exports = {
  getMean: getMean,
  formatTime: formatTime,
  getMaxValue:getMaxValue,
  getMinValue:getMinValue,
  getDataArray:getDataArray
}